Glassary - B

Backing paint:
a form of opacifier, see also spandrel panels, or a protective coating applied to mirrors.

Balustrade:
a term commonly used for a barrier, protecting a drop, which comes up to about waist height. See also information in Technical Bulletins Glass and Safety and Glass and Building Regulations – Stairs, Ramps and Barriers.

Barrier:
structures designed to either guide the direction of pedestrian traffic or to provide a guarding to the edges of drops. See also information in Technical Bulletins Glass and Safety and Glass and Building Regulations – Stair, Ramps and Barriers.

Base glass:
a term used to describe the glass, which is subsequently processed, e.g. acid etching, sand blasting, or coated glass.

Bead:
see glazing bead.

Bent glass:
an alternative term for curved glass.

Bevelling:
decorative process, of grinding a portion off the edge of the glass, to form a shallow angled face, which is subsequently polished. See Product Data Sheet Pilkington Bevelled Decorative Glass.

Blast resistance:
The ability of a particular type of glass to either withstand explosion pressure waves without breaking or to remain in position if broken. See Technical Bulletin Glass and Security.

Body Tinted Float:
see tinted float.

Bomb Blast:
strictly the high pressure wave of gases (the blast wave) that move rapidly away from an explosion. However bomb blast will often refer to the damage caused by the blast wave and by any fragments associated with the bomb. These fragments can be part of the bomb, any container or vehicle it was carried in and any material that was carried along by the blast wave. See also blast resistance and Technical Bulletin Glass and Security.

Borosilicate glass:
Glass with increased amounts of Boron. This means that the glass melts at a higher temperature than conventional soda lime silicate glass. Pyran from Schott Glass is an example of a Borosilicate Fire Resistant Glass.

Bow:
a form of distortion of toughened glass or heat strengthened glass. Bow may vary depending on the glass type/thickness, size, aspect ratio and other factors. It is measured with the glass in the vertical plane and supported at quarter points. The maximum deviation from a straight edge is measured on the concave surface.

BR1:
BS EN1063 classification for bullet resistant glass to withstand .22 Rifle

BR2:
BS EN1063 classification for bullet resistant glass to withstand 9mm Parabellum Handgun = G0

BR3:
BS EN1063 classification for bullet resistant glass to withstand .357 Magnum Handgun = G1

BR4:
BS EN1063 classification for bullet resistant glass to withstand .44 Magnum Handgun = G2

BR5:
BS EN1063 classification for bullet resistant glass to withstand 5.56mm Rifle = R1

BR6:
BS EN1063 classification for bullet resistant glass to withstand 7.62mm Rifle = R2


See also bullet resistance and Technical Bulletin glass and Security.

Brass Plating:
a term sometimes used when a customer buys bulk loads of a product through a merchant, who then arranges for the factory to deliver direct to his customer. The merchant usually does not see the glass involved all he does is raise an invoice.

Break Safely:
see safe breakage.

Brewster’s Fringes:
an effect like a rainbow visible under certain lighting conditions, produced in an insulating unit when the two panes of glass are almost exactly parallel to each other.

Brilliant cutting:
the manufacture of a decorative polished V-shaped notch in the surface of the glass. The notch may be straight or curved. See Product Data Sheet Pilkington Brilliant Cut Decorative Glass.

Brise soleil:
a partial shading device, usually above a window on the exterior of the building.

Brocade™:
Pilkington Brocade™ is the brand name for one of the Pilkington Oriel™ range of acid etched decorative glass. See consumer leaflet Pilkington Texture Glass™ for further details.

BS#:
stands for British Standard #. BS6262 part 4 is a safety glazing standard. A full list of glass related British Standards appears at the back of this guide.

BS EN #:
as European standards are agreed they are adopted as British Standards and so get a BS EN number. BS EN 1063 : 2000 is the bullet resistant standard. A full list of these appears with the British Standards at the back of this guide.

Bubble:
depending on context this could be:

• a bubble of air trapped between interlayers in a laminated glass, or
• a gas bubble that has become trapped within a piece of glass during manufacture.

Bullet Resistance:
the ability of a particular type of glass to withstand armed attack using a particular type of weapon not just by stopping the bullets, but also in terms of the spall ejected from the opposite face by the impact. BS 5051 grades bullet resistance with reduced spall (RS) from G0 through G1 and G2, for handguns, to R1 and R2 for rifles in order of stopping power, with a separate grade S86 for shotguns. This is being replaced by EN1063 standard see BR1 – BR6. See also Technical Bulletin Glass and Security

Bushes:
nylon or hard fibre ferrules used round the shanks of bolts in bolted connections, to prevent direct contact between the bolt and the glass. Often used in the Balustrades and in the Pilkington Planar™ System (see Pilkington Architectural Information on CD-ROM for further details.)

Butt joint:
a joint between the edges of adjacent panes, which have no frame, but are filled with adhesive sealant, commonly silicone sealant